MSc

The study entitled “Foliar nutrition with calcium and micronutrients for growth and yield enhancement in papaya (Carica papaya L.)” was conducted at Department of Fruit Science, College of Agriculture Vellayani, from 2019 April to 2020 April. Micronutrients and secondary nutrients like calcium play a major role in crop production due to their essentiality in plant metabolism and adverse effect that manifest due to their deficiency. The present work was undertaken to assess the effect of foliar application of micronutrients and calcium on growth, yield and quality of papaya.
The field experiment was laid out in Randomized Block Design (RBD) with 9 treatments and 3 replications. Surya, IIHR (Indian Institute of Horticultural Research) gynodioecious variety was used for the research purpose. Treatments were T1- Borax (0.5%), T2 - Zinc sulphate (0.5%) and T3 - Calcium nitrate (0.5%), T4 - T1 + T3, T5 - T1 + T2, T6 - T2 + T3, T7 - T1 + T2 + T3, T8 - Water spray and T9 – Control (KAU POP). Treatments from T1 to T8 were applied at 4th and 7th months after planting. Organic manure (10 kg FYM plant-1) and NPK (240: 240: 480 g plant-1 year-1) were given uniformly to all treatments as soil application as per KAU POP recommendation.
Treatment with foliar application of Borax (0.5%), Zinc sulphate (0.5%) and Calcium nitrate (0.5%) increased the biometric parameters like plant height and number of leaves at 6 MAP, 8 MAP,10 MAP and 12 MAP. A significant increase in plant girth at all stages of growth was observed for the same treatment.
From the present investigation, it was found that foliar application of Borax (0.5%), Zinc sulphate (0.5%) along with Calcium nitrate (0.5%) reduced the height at first flowering, days to flowering, duration for harvest of papaya fruit and increased the number of female plants than that of bisexual plants, fruit set percent and number of flowers per cluster.
The results indicated that yield characters such as fruit weight, fruit length, fruit girth, fruit volume, pulp percentage, flesh thickness, number of fruits per plant
and total yield per plant were highest with the combined application of Borax, Zinc sulphate and Calcium nitrate @ 0.5% respectively as foliar spray, where, number of seeds per fruit and days taken for maturity of fruits reduced significantly for the same treatment.
With regard to qualitative attributes studied TSS, total carotenoids, ascorbic acid, total sugar, reducing sugar, colour of pulp and peel and firmness of pulp were shown positive response with the spray of Borax (0.5%), Zinc sulphate (0.5%) along with Calcium nitrate (0.5%) however, reduction in acidity was found with the same treatment. Water spray recorded the highest value for non-reducing sugar content in papaya.
The foliar application of Borax (0.5%), Zinc sulphate (0.5%) and Calcium nitrate (0.5%) increased the organoleptic qualities like appearance, colour, texture, taste, flavour and overall acceptability. Shelf life of papaya fruits were longer with the same treatment.
From this study it was observed that soil parameters like soil pH, EC, organic carbon, available nitrogen, phosphorous, potassium, boron, zinc and calcium did not show any significant variation with the foliar application of micronutrients and calcium.
Data from the plant analysis and fruit analysis of papaya showed that nitrogen, phosphorous, boron, zinc and calcium content was highest with the foliar application of Borax (0.5%), Zinc sulphate (0.5%) and Calcium nitrate (0.5%). But Potassium content in both leaf petiole and fruit was highest for the plants treated with Borax (0.5%) and Zinc sulphate (0.5%) foliar spray.
Foot rot and leaf spot incidence were observed in the papaya field. Proper plant protection measures controlled the infestation which was less than 1 percent.
The highest net income and B:C ratio was observed with the foliar application of Borax (0.5%), Zinc sulphate (0.5%) and Calcium nitrate (0.5%).
From the above findings, it was concluded that foliar application of Borax (0.5%), Zinc sulphate (0.5%), Calcium nitrate (0.5%) at 4th and 7th months after planting along with the application of organic manure (10 kg FYM plant-1) and NPK (240: 240: 480 g plant-1 year-1) had increased the growth, yield and quality characteristics of papaya and it was economically viable too.